Die for drawing angular tubing



(No Model.)

' E. DEWS.

DIE FOB. DRAWING ANGULAR TUBING.

' No. 282,859. Patented Aug. '7, 1883.

ATENT CFFICE.

EDXVINDEVVS, OF ANSONIA, CONNECTICUT.

DIE FOR DRAWING ANGULAR TUBING.

.srncrricnrron forming part of Letters Patent No. 282,859, dated August7, 1883.

Application filed April 27,1883. (No model.)

To all whom, it may concern Be it known that I, EDWIN Dnws, of Ansonia,in the county of New Haven and State of Connecticut, have invented a newImprove ment in Method of and Dies for Forming Angular Tubing; and I dohereby declare the following, when taken in connection with accompanyingdrawings and the letters of reference marked thereon, to be a full,clear, and exact description of the same, and which said drawingsconstitute part of this specification, and represent, in

Figure 1, a view of the improved die from the entering side, Fig. 2, atransverse section of the same; Fig. 3, a perspective view of thepartially-formed tube as it comes from this die; Fig. 4, a transversesection of the same tube, the joint closed and brazed preparatory to thefinal drawing; Fig. 5, the usual dies for final or finished drawing;Fig. 6, the finished tube as it comes from the finishing-die; Fig. 7, a.die embodying my invention as applied to drawing triangular tubing.

This invention relates to an improvement in the method of and dies fordrawing tubing of square or angular shape. The usual method of drawingthis class of tubing has been to first form a round tube from a strip ofsheet metal and braze the meeting edges. This round tube was then drawnthrough a die resembling the final shape which the tube was to be, andpartially formedthat is, what is commonly termed broke down. Then thepartially-shaped tube was taken to a die of the exact finished shape anddrawn through that die. But in this 0011- struction it is impossible tomake perfect angles-that is, coming from the last or finishing die, theangle would not be quite filled, but left a little rounding.

.The object of my invention is to simplify the process of drawing thetube, as well as to produce an angular tube in which the angles will becompletely and perfectly filled; and my invention consists in the dies,as hereinafter described, and more particularly recited in the claims.

I will describe my invention as applied to forming a square tube.

The first die is represented at A, Figs. 1 and 2. This consists of ablank of suitable metal, through which is an aperture, a, a littlegreater in extent than the tube to be finished. On one side it has afunnel-shaped flaring mouth, I). The opening a has its one side, (I,slightly longer than one of the sides of the finished tube. The twosides 6 e are about may be differently shaped, it only being es- Ysential that that side shall be recessed to make it higher in the centerthan at the sides .9 e. The funnel-shaped mouth 1) leads gradually intothis dieopening a, as shown.

Instead of forming the round tube and brazing the edges, as hithertopracticed, I take a fiat strip of sheet metal and bend the first end tosomething near the shape of the opening a, and so as to enter theopening, the two edges meeting in the recessed portion h of the side f.Then I draw the strip through the die in the usual manner of drawingtubing, which brings the blank into the shape seen in Fig. 3, the twoedges '5 i nearly meeting each other, but inclined downward from theiredge, as there shown. v The angles are partially formed, as seen in thatfigure. run through between the two edges to brighten them and fit themfor brazing. Then the edges are bent down and brought together, as seenin Fig. 4, and then brazed in the usual manner. Next the blank thusprepared is taken to the drawing-die B in the usual manner, the openingZ of which is of the exact shape of the to-be-finished tube and slightlysmaller in area than the opening a in the forming-die. Through this diethe tube is drawn in the usual manner,-and the surplus metal left at Atool or cutter is then or near the angles of the blank is forced intothe angles to completely shape them, as seen in Fig. 6. By this methodof drawing angular tubing I save one operation of first forma triangularis required, the opening in the die .will be as seen in Fig. 7, the twosides m m diverging toa little greater extent than will the finishedtube, the upper side, 71, having substantially the same recess, h, as inthe square die. For other shapes, the one side where the edges meet mustbe recessed to allow them to turn out from the plane of that side, so asto permit the dressing or scratching out of the IQ joint preparatory tobrazing, and then to be hammered down.

I claim' 1. The method herein described for making angular tubing,consisting in first drawing the blank strip through a die having anumber of sides corresponding to the number of sides of the tube to bedrawn, the side where the two edges of the blank will meet greater thanthe opposite or adjacent sides, and: recessed to permit the edges of theblank to turn outward from the plane of that side, the-two edges thenhammered down and brazed, and finally draw-- ing the thuspartially-formed tube through a die of the shape of the finished tube,substan-

